Jonathan Ive, Apple's chief design officer, left, looks at some iPhone models with CEO Tim Cook during an event to announce new products Wednesday in Cupertino, Calif.

CUPERTINO, Calif. — Apple unveiled three new iPhones on Wednesday, including its biggest and most expensive model yet, as the company seeks to widen the product’s appeal amid slowing sales.

CEO Tim Cook showed off the iPhone XS Max, which has a bigger screen than the one on last year’s dramatically designed model, the iPhone X. It’ll cost about $1,100, topping the iPhone X, which at $1,000 seemed jaw-dropping at the time. An updated iPhone X, now called the XS, stays at $1,000.

As with the iPhone X, both new phones have screens that run from edge to edge, an effort to maximize the display without making the phone too awkward to hold. The screen needs no backlight, so black would appear as truly black rather than simply dark. The Max model looks to be about the size of the iPhone 8 Plus, though the screen size is much larger.

The iPhone XS Max, which will be available on Sept. 21 — with orders open the week before — represents Apple’s attempt to feed consumers’ appetite for increasingly larger screens as they rely on smart phones to watch and record video, as well as take photos wherever they are.

By making more expensive iPhones, Apple has been able to boost its profits despite waning demand as people upgrade phones less frequently. IPhones fetched an average price of $724 during the April-June period, a nearly 20 percent increase from a year earlier.

Apple also showed off a cheaper iPhone, called the iPhone XR. It has a traditional, lower-quality screen and an aluminum body; it’s physically smaller than the iPhone 8 Plus but has a bigger screen. It’ll cost roughly $750 and come out on Oct. 26.

All three new models join the iPhone X in getting rid of the home button to make room for more screen. They will have facial-recognition technology to unlock the device.

Apple also said that its next major update to its iOS operating system will come Tuesday, followed a week later by a Mac software update.

Apple also announced updates that push its Apple Watch further into medical device territory. It has a larger screen and a built-in heart sensor that the company said can detect irregular heart rates and perform an electrocardiogram. The latter feature has been cleared by the U.S. Food and Drug Administration, the company said.